Method of fault location on electrical conductors.



H. M. FRIENDLY. METHOD OF FAULT LOCATION 0N ELECTRICAL 'GONDUGTORS.

APPLICATION FILED MAY 13.1907.

Patented Aug. 6, 1912.

2 SHEETS-SEEBT 1.

a $3 4 5 6 6 7 8 A9 m 1 E 2 m ZAIHWG 7. 1 l o. P s

H. M. FRIENDLY. METHOD OF FAULT LOGATION 0N ELECTRICAL GONDUGTORS.

APPLICATION FILED MAY13. 1907.

Patented Aug. 6, 1912.-

' 2 SHEETS-SHEET 2.

EMm /I/ new! I HERBERT HQ FRIENDLY, F PORT hm, UM.

METfiOD 01' FAULT LOCATION ON ELBCTBIGAI ICOIIDUCTOM.

To all whom 1'! may concern:

- Be it known that I, Hnnnnn'r M. FRIENDLY,

v a Citizen of the United States, of America,

and a resident of Portland, county of Mult- -nomah, and State of Oregon,have invented a new and useful. Improvement in Methods of Fault Locationon Electrical Conductors,

of which the following is a specification.

I My invention relates to that class of electrical testing devicesintended for use in l0- eating. grounds or crosses on electricalconductors in cables'or on insulators, and involving the use ofadjustable resistances and of a galvanometer or other current-detectingdevice.

It is well known to utilize adjustable re.-

' sistances and galvanometers or other current detectors, in connectionwith sources of current for locating grounds and crosses upon lines; butin all'the methods which are availableior use with apparatus of limitedcomplication and reasonable scope, a certain amount of mathematicalcalculation is necessary after the manipulation of the instruments.has-been completed. For the reason that such calculations are necessaryand because they involve the use of mathematical processes not familiarto all persons, fault location is an art which has remained relativelyunknown to niany'persons v vli'ose 0ccupations otherwise would adoptthemto conduct such undertakings.

invention enables fault locatinns 'to be made with a minimum ofoperations and calculations, rendering possible the formulation ofspecific instructions which need but to be followed by a person of usualintelliwill - diagrammatic arrangement of the other elements associatedwith said commutator in one form of a-complete testing set made inaccordance with my invention; Fig. 2 IS a schematic illustration-of oneof the cases of test; 3 is aschematicillustration of a case 'of'testing.using an additional, and, if

desired, uncalibrated resistance; Fig. 4 is a schematic illustration ofa case of testing involving another relation of the resistances;

Specification of Letters Patent.

Application filed m 13, 1901. serm'xo. $78,331.

Patented Aug. 8, 1312.

and Fig. 5 is a schematic illustration of a case of testing involving anadjustable slide wire bridge.

Similar characters refer to similar parts throughout the several views.

In Fig. l are contained the elements of illustration required to makeclear the construction of the commutator of my inven- .tion, this beinga device of the general form commonly used in rheostats and resistanceboxes having conducting blocks mounted on an insulating support, theseblocks being arranged as terminals of various elements of the circuitsand adapted to receive between them conical conducting plugs. The sidesof the blocks being drilled and reamed to form conical holes, theconical plugs serve to join the blocks together wherever inserted, andin the arrangement which I illustrate, a wide variety of modificationsmay'be made upon the circuits. The conducting blocks of the commutatorare indicatedv by the reference letters, 0, d, e, f, g, h, i, k, 1, m,n, o, p and s. The conical plugs are omitted from the figure: They areof well known form and may be inserted into any of the holes between theblocks in order to bring about'the desired circuit arrangements. Theconical holes which may receive such plugs are indicated by thenumerals, 1 to 23, inclusive. The

blocks are secured to a flat insulating support, which latter is notshown in the drawings, and the binding posts, 25, 26, E, 30 and 31, thetwo .keys formed respectively of the parts 27 and 28, and the parts 32,33 and 34, and the galvanometer G, are associated with said hlocks,preferably by being secured to the same plate. The zigzag lines, a, b,r, and r represent suitable resistances. adjustable betvi'eiln cer-'tain predetermined limits, in any @itable.

manner, as by the withdrawal or iiisertion of plugs in an ordinary plugrheostat, by the moving of a pivoted arm over contact points havingresisiances connected between them, by the moving of a contact along abare resistance wire, or in any other of the Ways well known to the artof electrical testing. Theresistance' r must be adjustable to zero asone of its limits. It is optional whether these adjustable resistancesa, b,.'r and r be associated with the commutator as a unit.' They may bemounted with equal accuracy of result inseparate cases, al-

to determine'the location of a ground or' lion in1thegalvanomcter.

though connected to circuits of the commutator as indicated in Fig. 1.This optional separation is also permissible in the case of thegalvanometer and the keys.

The ofiice of the commutator is to provide convenient methods ofswitching, by which the circuit relations requir ddor the tests which Idescribe may be readily obtained. Scrutiny of the circuits iii-Fig. 1will 'make plain the considerable latitude of arrange ment-of parts thatmaybe secured by inserting plugs in the variously numbered holes, thuselectrically joining the variously-lettered blocks; it is not meantthatall-of the plug holes shall be filled with plugs for agiven test, orthat any tests are possible with all of the holes unplugged." As will befurther described, certain conditions of plugs will place the elementsinto certain required circuitarrangements.

It is assumed at the outset'th'at the vari ous ordinary methods oftesting for the value of an unknown resistance by the \Yheatslone bridgeprinciple are well known, 4

and that that variation in the Wheatstone bridge principle which isknown as the Varlcy loop test is also well understood, as it is thesemethods which are by far the most widely used in resistancemeasurements,"

particularly lines.

Considering the case of a test to be made upon telegraph and telephonecross upon one of two wires, one of the wires used in the test being'clear'of any' fault, these two wires being joined atthe distant end,-itwill easily be seen that the ordinary Varley loop test may be applied.In this case a calibrated resistance, such as r, would be inserted inthe conductor leading from one terminal of the galvanometer to the wireR, being the resistance in ohms from the point of testing to the fault,f", b and (1 being the respective arms of-the bridge in the generalrelation shown in the figure, L being the total series resistance-0t thetwo wires under test, or, ,in other Words. of the loop,

and v.- .heing the resistance of the rheostat as varied-do n'oduce: acondition of no deflec- 'l'hewthl'ee' distinctste'p's fim'the ordina ryi oil gv loop lost as poi-ft mc i y my method may .i rulcrstood by hr,-g,more par-' tu-uhu the, exactwonditicns shown Fig .3 .gto, he notedth'atdh'enumerals associated with-the drawing by small arrows havereference to the connecting plugs in the commutator shown in Fig. 1. Forexample, the numeral 11 indicates that at the point referred to by itsarrow the hole 11 ofthe commutator is plugged up, thus producing theexact circuit condition shown at that point in Fig. 2. Referencenumerals,

sucli'.as.ii0,' shown adjacent 'to a point of the circuit but withoutthe arrow indicate parts other than plug-hole parts of the com mutator.Arranging the commutator plugs as indicated, with a plug additionally inthe hole :19, but with none in the hole 23, and adjusting the arms a andb. to have a ratio to each other of 1 to 10, or -1' to 100, or "in anyother ratio of 1 to some power of 10, the resistance 13 may bevarieduntil'no deflection 'of the galvanometer G occurs when'the keys "havinglevers 27 and-32 aredepressed. Under-the conditions established; thetest made will have been a simpleWheatstone bridge"measurement of theresistance of the loop L,- and this resistance is determined at once bymultiplying the determined resistance rby the previously establishedratio of v a to b. -Knowing the value thusEde-termined,

unplugging the -hole;19, plugging upothe 1 hole 23 so as to apply thebattery connection through'the fault at f and E, the resistance a 1-maybe again adjustedto a balance- All quantities in the second membervof the; Varley loop equat on are now known, and

the resistance R to the fault'm h be determi ncd.-

The, foregoing illustrates the application of the commutatdr of myinvention to two of the principal useful forms of testing involv-- ingsubsequent calculations, that is, to the measurement of resistances, asof the loop "L, iltig. 2, by the simple :Vheatstime bridge method, andto the ordinary application of the bridge to Varley, loop methods. meansof any c ommut-ator or master-switch I a m enabled to perform many otherof. the

,110 ordii a f velldtnown; tests to whichthew ,'lleatstone.bridgeissgenerally ad aptable'.,;

It is, however, to a new processor method of n'ieasu'rement"ot.faultlocation that my in-- 've'ntion is directed. i l

In the Varley loop V test, asoidinarily the two wire, under test sccond,thcbalancing'ot the good wire in series with .the rc-I practised, threesteps flare, necessary; first, J the vdctern'rnt on .of the loopresistance of,

mote portion of the faulty-wire againsta known variable resistanceIILSKIfltlfiAVltllthe near portion of the faultywire, iand, third,

the sr'lbstitution ot the loop resistance dey termincd in thefirst step,and the resistance necessary to balance" as determined in; the;

second step, in the Varleyloop..o(p!al:ion;,.alreadygivcn, 1n ordertosolve for the; resistance to the fault on the faulty wire. Inlay theloop resistance L is 1 improved method,

4 solving for involved in the balancing vof the resistance 1?, and theresistance 9- then is retainedas a part of the circuit ofithe latertest. The introduction of the result of the first test into the secondtest thus is made automatically, the necessity of any knowledge on thepart of the operator of the loop resistance or of the absolute value ofthe r resistance is obviated. This method may now be understood byreferring to Fig. 3, bearing in mind the described meaning of referencenumerals accompanied by arrows. In addition to the inserted plugs asindicated in this figure, assume hole 23 to be pinged, hole 19 to beunplugged, and resistance r to be adjusted to zero; then the resistancer may be adjustettl to a balance of the galvauometer under any of alarge number of ratios between the bridge arms a and b; but for thisratio I nowchoose values of a and I), such that a will be Il/9f" 1/99,etc., of Z), the sum of a and I) being a Ways, in the presentillustration, some power of 19 when referred to a as a base. When abalance has been reached, unplug23 and: plug up 19 and once moremanipulate the keys, and, leaving r as adjusted, adjust r until abalance has n reached. I Then the resistance in ohms to the fault is theresistancermultiplied by the ratios of the arm 0, to the sum of the armsa and b. That this is so is readily proved. When hole 23 is plugged,grounding the batteary, and a balance is secured'b manipulating '1 7*being zero, I

p b 2* +3 v When hole 19 instead of Qa is plugged, and a balance againsecured, by manipulating 1 leaving r as adjusted,

, L b v Substituting this value for L in (l) and But with the valueschosen the sum ofa and 6 is always some power of l0 when referred to aas a. base; therefo i Bi a-l-h 10* and the i alue of R thereforebecomes,

'10 and the calculation is simply to divide the value of r by theparticular power of 10, or

J in other words to point off from the right of the adjusted value of ras many places as there are ciphers in the power, or units in the indexof the power.

It will be seen that the operations here are exceedingly simple, andwith the prerequisite bridge arm relations established, =no'realcalculations whatever are necessary,

It will be noticed that in the first sdjustment to galvanometer zero bythe use o resistance 7, something of the usual process of determiningthe value of theresistance r was accomplished, but in contradistinctionfrom methods requiringan exact determination of the numerical value ofthe resistance 1 my method takes no account ofthe nomion] numericalvalueof a" but only utilizes it in a way such that it finally disa pearsfrom the equation without its value liming been definitely determined,leaving that determination in the circuits-as a means to a final end,and not as an element of calculation. It Will thus be seen that theadjustable resistan e denominated? may for this test be any adjustableresistance but not necessarily a calibrated resistance. All that isrequired is that it be variable within reasonable limits,.and that itremain constant after adjustment only for the time required to completethe operations peculiar to the test.

Sometimes it is desirable, as a check method, or for other reasons, to"use a variable resistance in the limb of the line having no fault. Suchan 1.1mm eme shown in Fig. 4, the resistance r Icing placed in theopposite limb of the line from the resistance r. This arrangement isreadily accomplished with my commutator by inserting the plugs in thevarious proper holes as indicated by numerals in- Fig. 4. With theapparatus thus arranged, the test for the lo ation of the fault, f,maybe made as follows: Plug up 23, unplug J9, and adjust 1' to zero.Establish a relation of bridge arms in which the sum of a and b is theproduct of b and some power of 10; adjust r to the balance of thegalvanometer. New, unplug 23 and plug up 19, and make the arms a and 1)equal to each other, a

ratio of. unity. Then adjust to a new balance of the gulvanometer. Theres1stance to the fault is then the resistance 1'.

divided by the ratio first established between Z) and the sum etc and b,or,

That this is so is thus first balance was obtaine (proved When the Ifaulty-which is the result. desired It as not hence,

Substituting this in 1 But, under other values assumed for a, and b,

It will be seen that the mathematical oper ations other thanbalancing"areonly with" 'relation to the sim'ple'iatios of the bridge arms, 'anda're accomplished by pointing ofi or. adding ciphers 'onl Referring n'oWto ,lligL- Sk-SS) is an ad usstablc resistance ire, rod, or similaruniform conductor, 37 and with the resistan e 39; 40 is a sea'le' alStlIlg in determining the relation of the resistance 39 and the contactpoints "'37 'antlfiS." By the adjustment of total amount of; shuntivitli the he tiitz'i'l" 'i' esista'nce included by on til maybediv-itledfinto tii o parts, that ii'lehuled' between the contact'phints "3 and 3S eurl'e: spoil ling to arm a in the previons figi'ires,and' 'the remaining portion ehrrespo'nding' to the arm 5. \Vith thisarrangement and the pi'hcess described \vit'lereliition to- Fig. 3-,in'ost ra id; locations can he made. Byan a r 'i-angizjemfe calculationof the resistance in ohn'is to the always necessary,l however, to know,.the. r c-, sistanee in ohms, as it ,is frequently important to kuow'thedistance infeet or meters, it the conductor he in'a cable." Tn fact. thedetermination of ,the resistance to the fault is usually used as abasis, oflltitcrn in ing the distance to the fault. My method is capableof quite as eonvcnieiithse to read directly,

in terms of distance as in terms of resist- 38 are respectively contactpoints cagable of adjustable contact;

'38 in contact tv it' hElEt, the ;t ancg thus included g'ralrariometerG- in'ay he -ar'-'; ranged; by.=moving 87'with "relation to tof parts"converting the po'si-= an'ce, a11d" loy the application of the qs ame if,principles'as I have already described.

as 1 is' t' o the length per ohm of the con-f diicto'r under test. 7Thus, in 'the caseof feet,

fe'etperohm of the conductor, or in" the case of miles, as 1 is tothe'miles per "ohin of the conductori- To illustrate; suppose aconduetor having 63- feet per'ohrn test as "in Fig.3, n amm might hegiven 4 62, equa1't0 e3 1; Then the formula withltliesefx alues,

whencefita followe that 13 1 In other *r is equal to the distance in,ll'm-a the conductor-under' test of resistance oi $335. ft. vper ohm,the. hridge might hesetto l and 7 respectively for the arms, onto It)and I feast the ratio is the same.

ohm, etc, depends uphn'the specific resist perature of the conductor andthe conductor material, and can lie 'determined'lW welllgnown means, asfrom tables. In the ease, of copper, for example, the resistance of ainch in diameter, maybe said to be 10.8'ol1ms. it the cross section of acopper wire exohni'of the .wire; Afootof wireflone-thoumil meterresistance may be employed, the result of division being in terms ofyards per ohm, miles per 0l1m,mete1"s. per ohm, etc. Applying thismatter-to the simplification ()fltStS to be read in distance, I mayadjust the bridge 'arms,f0r example, in Fig. ,3', so that arm a isaltd'b'asthe mil foot 0i resistance 95 i i. of eopp'e'r-1s2to .titie"aree incircular Hills of the wire under test. On balancing to a zero "1Generally stated, the principle asapplying t'o resistance determinationsis that one bridge arm shall be to the sum-of the arms as-l i's to a,powerot 10. In the case-(it re' sults to he reached in'tcrmsofdistance, the prin'ciplef' may be stated as heinfz thatone bridge armshall be to the sum of the arms I Were'under test 1 In making the Varleyloopwhichfinallv"expresses the result, hecon'tes:

words, the adjusted .Jralne ojiz the resistance:

v v feetfto the fault, and the instrument:thus used 15' direct-M ohms,sineein either The quantity, :t'cetv per ohm, meters per ance, the areaof cross section, and the temto, the sum of the a value ofnnity and thearm 7) a value of in which R istheresistancein ohms to ,the. 'fau'lti-Lt now D be taken'as the d stance int'eet'te the fault itis'ei'identthat 13 633,.

' foot of circular wire, one-thousandth at an pressed in circular millsbe divided by 10.8 i the result will heth'e number of feet. per

sandth of an i nch in diameter called a mil-foot; similarly a mil-yard,-m l-mile' or movement of the galvanometer by adjustment of the tworesistances as described for that figure, such a value of r ijs"directly ,given as corresponds to the distance in feet to the fault Forexample, if the test were being applied to a faulty conductor in a cableformed of wires of #22 Brown & Sharpe. gage, the faulty conductor wouldbe looped with any good conductor at the distant end; the area of #22wire in circular mils being 642.8, and the mil-foot resistanceof copperbeing 10.8, the bridge would be respectively 10.8 for a aiid (642.8'10.8or) 632 ohms for 6.

Variety is possible in the method of calibratingthe scale. Two or morecalibrations a, scale for s may beused' Simultaneously. There may beific resistances, say for the unit of a mi -foot, the points on thescale being marked, Co per, Aluminum, Iron, Steel, B etc., and anotherscale of cross sections in circular mils, the divisions of-the latterscale being marked, #8 B. W. G., #12 B. a. s, #14- B. .& 8., etc. Inaddition to these special scales, the usual numerical scale mightbegivenfor general work. The user now de-' string to locate a faulton a circuitof #12 B, & S. copper wire would set 37 to Copper and 38 to #12 B. & S3and make the two adjustments of 1" and '1', the latter of which'would bea direct reading of the distance to the fault, in feet.

A slide Wire resistance is not an absolute necessity in this system ofcalibrations, butit seems the simplestto show in the drawingsaccompanying these specifications.

Having thus described my invention, what I claim as new and desire tosec'uteby United States Letters Patent is:

1. A process for the physical solution of electrical problemscomprising, first, a measurement as a preliminary step involved in thesolution of the problem, that measurement being made by the physicalsetting up of a condition in a measuring instrument, and, second, theattainment of the solution of the problem by a subsequent step involvingthe measurement made in the preliminary step,- wherein said measurementintroduced by the inclusion of the condition physically set up by thepreliminary step.

2. A process for the physical solution of electrical problemscomprising, first, a measurement involved in the solution of the problemas a preliminary step thereof, that measurement being made by thephysical settingup of a condition in a measuring instruL'icnt, and,second, the n'tl'aii'uncnt of the solution of the problem by asubsequent step involving the uicasurement llllHlCill the preliminarystep, wherein said i'neasuremcnt is introduced by the inclusion of thecondition physically sct up by the preliminary stop.

3. A process for the physical solution of electrical problems consistingof the attainment of a hysical condition involved the parts or functionsin value in any unit.

' 4. A process. for the physical solution of electrical problemsconsisting of'the attainment of a physical condition involved in thesolutipn o the problem and then the attainment of the solution of theproblem by a second and separatestep, the physical con dition attainedin the first step being involved in the secondstep without chan e, thecondition attained by the first step g ing taken as the zero conditionin the second step of the solution and a second measurement being madefrom that condition or adjustment. as a starting point.

5. A process for the physical solution of electrical problems consistingof the attainmentof a physical condition involved in the solution 0 theproblem and then the attainment of the solution of the problem by asecond and separate step, the physical condition attained in the firststep being in volved in the second step without change, the conditionattained by the first step of the solution and a second measurement being made from that condition or adjustment as a starting point, saidsecond measurement being readable directly in terms proper to constitutethe final solution of the problem.

6. A process for the physical solution of electrical problemscomprising,first, as a preliminary step involved in the solution thereof, theproduction of a condition by a method of test suitable to the needs or"the problem, and, second, the attainment of the solution of the problemby a subsequentstep involving a measurement determinable by the firstmethod of test, wherein such measurement is introduced by the inclusionin the subsequent step of the condition as produced by the preliminarystep.

7. A process for the physical solution of electrical problemscomprising, first, a preliminary ste made by the physical settingup'ol': a con ition or adjustment in a set of test apparatus, and,second, the attainment of thesolution of the problem by a subsequcnt-Step involving the physical quantities involved in the preliminary stepwherein said involved quantities are intrmiucod by the inclusion in thesecond step of the testing apparatus as physically adjusted by thepreliminary step.

8. A process for the physicalsolution of c. *ctrical problems,comprising, first. a measurement as a preliminary stop thereof, thatmeasurement being, made by the physiinstrument, and, second, theattainment of the solution of the problem by a subsequent step involvinga-quantity determinable by' the preliminary step, and ,wvherein saidquantity is introducedby the inclusion of the operations of thesubsequent step 0 the measuring instrument asphysically set up by thepreliminary step. a v

1 9. A. process for the physical solution of electrical problemscomprising first, a preliminary step made by the physical setting up ofa condition or adjustmentin a set of such as to .cause the reading astaken to constitute the'final solution-of the problem.

10. A process for the physical solution of electrical problemscomprising first, an adjustment as a preliminary step thereof, that Iadjustment being, made by the physical setting up ot a condition ofbalance in a set of testing apparatuaand second, a subsequent stepinvolving the physical quantities involved in the preliminarystep,wherein said quantities are introduced by the inclusion of conditionattained in the first'step, the balance being disturbed by a change incirtaken withthe changed condition of circuit, the new circuitarrangement including the apparatus of the preliminary test as adjustedin that test, and the test apparatus used in the first test being takenunchanged inadjustment and being used as alzero or starting point forthe adjustment and read of the final ste'p being made in such terms asto constitute the final solution of the problem. I I

Signed by ine at Portland, county of Multno nah, and State of Oregon, inthe presence of two Witnesses.

HERBERT M. FRIENDLY.

\Vitnesses M. S. FmnnDLY,

Hn'x RY I MA'rrnEW.

the physical ,units of test apparatus .in the cnits, and a new balanceor reading being ings of the secondstep, and the reading

